Convert OFF to AMF
Free OFF to AMF converter that runs in your browser. See real dimensions before you download.
How to convert OFF to AMF
- Drop your OFF file onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose AMF as the output and click Convert. Several files download as one ZIP.
What carries over from OFF to AMF
| OFF | AMF | Result | |
|---|---|---|---|
| Colour / materials | No | Yes | — |
| Textures | No | No | — |
| Units stored in file | No | Yes | Written as mm |
| Separate parts | No | Yes | — |
| Usual up axis | Z | Z | Unchanged |
About OFF files
OFF, the Object File Format, was defined for Geomview, an interactive geometry viewer developed at the Geometry Center at the University of Minnesota in the 1990s. A file is plain text. The first line holds the keyword OFF, the second gives the counts of vertices, faces and edges, then each vertex appears as three coordinates and each face as a vertex count followed by index numbers. Variants add colour (COFF), normals (NOFF) or texture coordinates (STOFF) through prefixes, and colour is optional at the end of each line. The simplicity made it a favourite in computational geometry, and benchmark sets such as ModelNet used it for machine-learning research on shape classification. CGAL and libigl read and write it directly. It has no units, materials or scene structure, so it is rarely a printing format, but converting it is common.
About AMF files
AMF was standardised as ASTM F2915 and later ISO/ASTM 52915, with the aim of fixing the shortcomings of STL for additive manufacturing. A file is XML, optionally compressed as a ZIP, and describes one or more objects made of a vertex list and volumes of triangles. Unlike STL, it declares units, such as millimetre, inch or micrometre, and can attach colours and materials to volumes or even to individual triangles, with gradients between them. The specification also allows curved triangles, constellations that arrange several objects, and custom metadata. In practice it was overtaken by 3MF, which came from industry backers and gained support in Windows and the main slicers. AMF files still appear from some multi-material printers and research tools, and from older exporters in Cura, Slic3r and Meshmixer.
3D printing notes
Few slicers open OFF directly, so the usual job is converting a research or dataset mesh into STL or 3MF. Dataset meshes such as those in ModelNet are often unit-less, normalised to a small box and not designed for printing, so they can be scaled to a size of one unit and have thin shells or holes. Set the printed size deliberately, then run a repair. MeshShift reads and writes OFF in the browser, shows real dimensions, lets you rescale, and converts to STL, 3MF, OBJ, GLB or PLY. Its print check finds holes and flipped normals and can rebuild a closed solid at the same size before you slice.
Frequently asked questions
Is this OFF to AMF converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your OFF file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.
What is an OFF file used for?
OFF is a simple mesh format used mainly in geometry processing and machine-learning research. Datasets like ModelNet ship as OFF because the format is easy to parse. It is a plain text list of vertices and faces.
Is AMF better than STL?
On paper, yes: it has units, colour, materials and several objects. In practice STL is accepted everywhere and AMF is not, and 3MF now fills the same role with much wider support. Use AMF only when a specific tool or workflow requires it.